The Last Supper is the most reproduced religious image in Western history. It has been printed on tea towels, translated into tapestries, parodied in advertising, and referenced in films. Most people have seen some version of it hundreds of times. Very few people have seen the original, which covers an entire wall of a refectory in Milan, and which looks nothing like any reproduction you have ever encountered.
Leonardo da Vinci painted The Last Supper between approximately 1495 and 1498, commissioned by Ludovico Sforza, Duke of Milan, for the dining hall of the convent of Santa Maria delle Grazie. The moment depicted is from the Gospel of John: Jesus has just announced that one of the twelve apostles will betray him. Leonardo chose the instant of psychological revelation, the split second after the announcement, when each apostle reacts in his own way to the news.
The Composition
Leonardo's achievement in the composition is to combine a clear, stable structure with intense psychological complexity. The room in the fresco uses linear perspective that converges on a single vanishing point, precisely at Christ's right temple. All the architectural lines, the ceiling beams, the tapestries on the walls, the table edges, draw the eye directly to Jesus. The space is mathematically organized around him.
Against this static geometry, Leonardo placed twelve figures in violent psychological motion. He grouped the apostles in four sets of three, each group responding to Christ's announcement as a unit, yet with each individual within the group expressing a different form of the same emotion. The far left group, Peter, Andrew, and Bartholomew, surge toward Christ. John, immediately to Christ's right, leans away in anguish. To Christ's left, Thomas raises a finger (later echoed in the Sistine Chapel ceiling's Creation of Adam), James the Greater spreads his arms wide, and Philip stands and appeals to Christ directly.

The Last Supper, Leonardo da Vinci, ca. 1495-1498. Refectory of Santa Maria delle Grazie, Milan. Wikimedia Commons.
Where Is Judas?
Tradition in depictions of the Last Supper placed Judas isolated on the opposite side of the table from the other apostles, marking him out visually as the betrayer. Leonardo refused this convention. He seated all thirteen figures on the same side of the table, facing the viewer, so that no one is visually excluded. Instead, he identified Judas by other means: he is the fourth figure from the left, leaning back from the table in a posture of guilty withdrawal, his face in shadow, his hand tightly grasping a small bag, presumably the thirty pieces of silver he received for his betrayal.
Judas's isolation is psychological rather than spatial. He recoils from the light that falls on the others. He is the only figure at the table who responds to Christ's announcement with concealment rather than agitation or anguish.
The Technical Problem
Leonardo's choice of medium was calamitous in the long run, and responsible for much of what we now see. Standard fresco technique required painting on wet plaster so that the pigments bonded chemically as the plaster dried. The result was extremely durable. Leonardo, however, wanted to achieve effects of light and shadow that the fresco method, requiring speed, would not allow. He worked slowly, revising and layering. He painted on dry plaster, using a mixture of tempera and oil over a preparatory layer of ground and gesso.
The surface began to deteriorate within Leonardo's own lifetime. By the early sixteenth century, visitors were already noting that the painting was damaged. By the eighteenth century, the refectory had been used as a stable, the wall had been repeatedly flooded, and a doorway had been cut through the lower portion of the composition, removing the feet of Christ and several apostles. The painting survived a Second World War bombing in 1943 that destroyed the rest of the refectory ceiling and walls: the Last Supper wall alone was left standing.
Between 1978 and 1999, an extensive restoration project worked to stabilize and clean the surviving paint. The results are striking and, for some, disturbing. The restored painting is quieter and more muted than the dramatic reproductions suggest. Many details long thought to be part of Leonardo's original composition were revealed to be later overpainting. The colors are different from every reproduction made before the restoration.
Five Centuries of Copies
Because the original was deteriorating so quickly, copies were made within decades of the painting's completion. A copy in oil on canvas by Giampietrino, made around 1520 with the assistance of Leonardo's workshop, now hangs in the Royal Academy of Arts in London and preserves many details, including the feet of the apostles, that were later lost or obscured in the original. Other early copies by Marco d'Oggiono and Andrea Solario are preserved in various European collections.
The proliferation of copies means that what most people carry in their minds as "the Last Supper" is actually a composite of many different versions, painted over five centuries by artists who were themselves working from earlier copies. The image has drifted far from Leonardo's original intention, acquiring conventions and details that Leonardo never included.
Visiting the Original
The original Last Supper is accessible by timed tickets only, with visits limited to fifteen minutes per group to control the humidity that has been the painting's most persistent enemy. The viewing experience is stark: the refectory is almost empty, the painting fills the entire end wall, and the fifteenth century still feels present in a way that no reproduction prepares you for. The scale is the first surprise. The figures are larger than life. Christ's hands are immediately visible from across the room, open on the table, calm at the center of everything.